000
FXUS61 KBTV 180223
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
1023 PM EDT Wed Apr 17 2024

.SYNOPSIS...
A weakening area of surface low pressure moving into the Great Lakes
region combined with embedded shortwave energy aloft will bring a
period of light rain to the forecast area late tonight through
Thursday. Dry conditions follow for Friday morning, but a cold front
passage in the afternoon and evening will bring an additional round
of light rain. Mostly dry conditions and seasonally cool
temperatures are expected for the weekend.

&&

.NEAR TERM /THROUGH THURSDAY NIGHT/...
As of 1020 PM EDT Wednesday...

Forecast remains very much on track. Only made minor changes to
the hourly temperatures and PoPs as SPC RAP mesoanalysis shows
a dry air mass remains in place across North Country.
Temperatures have responded to rather effective radiational
cooling region wide despite the thin mid and high clouds. Given
that dew points are in the upper 20s to low 30s, it is possible
that snow is mixed in with the rain showers down to 1000 ft
elevation during precipitation onset during the overnight hours thanks
to wet bulb cooling. However, no accumulations or travel
impacts are expected given the warm road temperatures and
overall light precipitation rates.

PREVIOUS DISCUSSION...

Overall the forecast for tonight through Thursday night remains
on track with a weakening are of surface low pressure tracking
into the Great Lakes region being the main feature of interest
for weather across the North Country and Vermont. Shortwave
energy ejecting out of the parent mid/upper level trough on
southwest flow will provide the support for showers to develop
late tonight through Thursday as a ribbon of enhanced low to mid
level moisture moves in on the nose of a modest 925-850mb jet.
Ahead of the precipitation, southeasterly winds look more robust
compared to the previous forecast with good mixing ahead of the
precipitation and 925mb winds in the favored downslope prone
regions topping out around 45kts. Think areas along the western
slopes of the Adirondacks and Green Mountains will see gusts in
excess of 35mph for a short period after midnight through midday
Thursday before the areal coverage of showers increases and the
low levels stabilize. Showers may linger into the first half of
Thursday night as well with low clouds and moisture potentially
supporting some areas of drizzle through the night as well.
Overall the basin average QPF will be light though, with
generally 0.2" or less across Vermont and up to a third of an
inch possible across northern New York. Min temps tonight and
Thursday night will be on the mild side of normal in the upper
30s to mid 40s, and highs won`t be much warmer on Thursday in
the mid 40s to low 50s.

&&

.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
As of 310 PM EDT Wednesday...As we transition further into Spring,
days like Friday will become increasingly common. Slated for Friday
will be a one-two combo with a prefrontal trough during the
afternoon and the actual front coming through after sunset. The
highest chances for showers will be Friday afternoon, but most
forcing will come from isentropic upglide. Overall, the better
dynamics are to our north, and the frontal boundary is diffuse.
Precipitation amounts will be at or less than 0.10" favoring
northern New York and the northern Greens. Breezy south to southwest
flow will yield wind gusts of 15 to 25 mph, especially in the
northern Champlain Valley and northern slopes of the Adirondacks.
High temperatures will mainly be in the 50s, with a few spot 60s in
warmer locales within the St. Lawrence and northern Champlain
Valley. Cold air before the front could bring a few summit snow
showers as temperatures sink into upper 30s to lower 40s at low
elevations, 30s in the Adirondack wilderness, and Mt. Marcy and
Whiteface into the upper 20s.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 310 PM EDT Wednesday...There are several vigorous shortwave
troughs that will traverse the region over the weekend into the new
week. However, none of them really tap into a tropical moisture
feed. The strongest one will swing through on Saturday. Although
surface moisture will be decreasing from a recent frontal passage
and surface pressures are rising, the vorticity advection with the
trough is quite strong and there will be steep low level lapse rates
with up to 100 J/kg of CAPE. It is difficult to say whether
precipitation can reach the ground. Forecast soundings depict very
dry near surface conditions. What this may do is produce virga that
also create gusty winds as the steep low-level lapse rates aid in
the acceleration of downdrafts in convective activity. For now, the
forecast depicts the highest precipitation chances along the
international border where the shortwave tracks and keeps conditions
dry south with wind gusts generally 25 to 30 mph, locally up to 35
mph.

The next shortwave trough moves in almost immediately behind the
previous system, racing through Saturday night. Ultimately, this
system will likely have too little moisture and will reinforce cool
air that should keep the region around seasonal norms. The next
upper trough will descend over Quebec Province late Sunday evening
into Monday, but the front is so diffuse and it will again be
moisture starved. Upper level troughiness gets briefly interrupted
by a weak ridge and south to southwest flow to produce some warmer
temperatures. However, by late next Tuesday evening into next
Wednesday, there is another trough. This one should have some more
moisture with it and have a larger impact on sensible weather
conditions with shower activity sliding in for the middle of next
week.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Through 00Z Friday...VFR conditions are expected to prevail for
the next 12 hours or so across the region. A slowly approaching
cold front will battle dry air as it moves into the forecast
area. MSS and SLK will be the first to experience some MVFR
conditions, though downsloping could provide SLK with some extra
hours of VFR before ceilings drop. Rain showers from the cold
front will be fairly light with limited precipitable water,
likely 5+ miles vis. After MVFR ceilings and occasional vis
reach the NY sites, this will progress northeastward into VT
sites slowly. Winds generally north/northeasterly will be
increasing around 06-12Z Thursday with gusts 15-30 knots and
direction turning more southeasterly. RUT has the potential to
see some low level wind shear around 11-18Z Thursday as well. Of
all sites, MSS is most likely to have IFR ceilings develop 15Z
Thursday onward, but confidence is not high at this time, so
this is not in the TAF.

Outlook...

Thursday Night: Mainly MVFR, with areas VFR possible. Chance
SHRA.
Friday: Mainly VFR, with local MVFR possible. Chance SHRA.
Friday Night: Mainly VFR, with areas MVFR possible. Chance SHRA.
Saturday: VFR. Chance SHRA.
Saturday Night: VFR. NO SIG WX.
Sunday: Mainly VFR, with areas MVFR possible. NO SIG WX.
Sunday Night: VFR. NO SIG WX.
Monday: VFR. NO SIG WX.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.

&&

$$
SYNOPSIS...Lahiff
NEAR TERM...Chai/Lahiff
SHORT TERM...Haynes
LONG TERM...Haynes
AVIATION...Storm